ASSOCIATION OF FERRITIN AND PLASMA IRON LEVELS AT TIME OF VACCINATION WITH THE IMMUNE RESPONSE TO SA

Giulia PESTONI¹, Anja FREI², Milo PUHAN², Diego MORETTI¹, Dominik MENGES², Pornpimol SCHEUCHZER¹, Julia BRAUN², Sarah HAILE², Tala BALLUZ², Christophe ZEDER³, Nicole STOFFEL^2,3, Michael ZIMMERMANN^2,3

¹University of Applied Sciences of South Switzerland (SUPSI) / Swiss Distance University of Applied Sciences (FFHS), Zürich, Switzerland
²Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zürich, Switzerland
³Laboratory of Nutrition and Metabolic Epigenetics, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
⁴Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom

Background: Iron status may affect the immune response following vaccination. We aimed to investigate whether ferritin and plasma iron at time of vaccination were associated with the development and temporal decay of immune response to SARS-CoV-2 vaccination over 26 weeks in the population-based Zurich SARS-CoV-2 Vaccine cohort.

Methods: Participants (n=572) were randomly recruited stratifying by age groups (18-64years, >65 years) and vaccine types (Pfizer-BioNTech BNT162b2, Modernam RNA-1273, Johnson&Johnson JNJ-78436735). Blood samples and self-administered questionnaires were collected at baseline and 4, 6, 13, and 26 weeks. Iron status was measured at baseline, whereas immunity markers at each time point. The association between iron parameters and immunity markers was investigated using linear mixed-effect models. Half-life was estimated using log(0.5)/model-coefficient.

Results: Mean age(±SD) was 56.0±18.1 years. Seropositivity at baseline was 11.5%. Geometric mean ferritin was 88.1 mg/L and mean plasma iron 0.82 mg/mL. Iron deficiency was generally low, with prevalence higher in females. In the longitudinal analysis, ferritin at time of vaccination was positively associated with Anti-S IgG Ab (b=0.004, 95% CI 0.002;0.007), and Anti-wildtype NAb (b=0.011, 95% CI 0.001;0.021), Anti-delta NAb (b=0.016, 95% CI 0.006;0.026), and Anti-omicron NAb neutralizing antibodies (b=0.013, 95% CI 0.003;0.024). Plasma iron results were generally not significant. Significantly lower half-life was observed in participants in the highest quartiles of ferritin concentrations, while no clear trend was observed for plasma iron. Conclusion: In this mostly iron replete cohort, ferritin at time of vaccination is was marginally associated with the vaccination-induced development of immune markers to SARS-CoV-2.